In recent years, maintenance and restoration of the ingestion and deglutition functions of elderly people have been pursued, and it is becoming increasingly necessary to elucidate those functions. The movement of the tongue is deeply involved in ingestion and deglutition, and sufficient tongue pressure is needed to form a food bolus and transfer it into the pharynx. Therefore, the measurement and analysis of tongue pressure have important implications. Moreover, measurements of a pressure related to the oral cavity are required for various other purposes.
As an apparatus for measuring a pressure related to the oral cavity, for example, Patent Document 1 discloses an apparatus for measuring the tongue pressure that uses a balloon as a pressure-receiving portion. This apparatus is arranged so that the balloon is inserted into the oral cavity and pressed by the tongue, and the air pressure is detected and converted into an electrical signal at a converting portion communicating with the balloon.
However, handling of the apparatus disclosed in Patent Document 1, such as the attachment and detachment of the balloon portion to and from the transducer, is not necessarily easy, so the apparatus has a problem with practicality. Moreover, since the apparatus employs a structure in which only the balloon is inserted into the oral cavity, in the case where a subject bites the balloon when applying a pressure thereon, a portion in the vicinity of an outlet of the balloon leading to the transducer is pressed down, resulting in a risk that the air pressure will not be transmitted properly to the transducer.
To address these issues, Patent Documents 2 and 3 disclose apparatuses for measuring a pressure related to the oral cavity, the apparatuses being arranged so that a balloon formed of an elastic material is attached to a probe tube and used as a probe, and the probe tube is connected to a pressure detector during use. The interior of the balloon communicates with the pressure detector via the probe tube, and the air pressure inside the balloon can be detected. The use of the probe tube improves the measurement stability as compared with the case where only a balloon is inserted into the oral cavity, facilitates the attachment and detachment of the probe, and increases the ease of handling. Furthermore, a configuration in which the probe tube is connected to a pressurizer as well as the pressure detector and the interior of the balloon is pressurized to a predetermined pressure by a pressurizing portion to increase the precision of the pressure measurement also is disclosed.    Patent Document 1: U.S. Pat. No. 5,609,161    Patent Document 2: JP 2005-296281A    Patent Document 3: JP 2001-275994A